Endocrine Abstracts

Phaeochromocytomas and paragangliomas arising as part of familial syndromes such as multiple endocrine neoplasia (MEN)2 or von-Hippel Lindau syndrome (VHL) are more likely to be malignant and multiple. Recently the role of mutations in the SDH genes (encoding subunits of succinate dehydrogenase) have also been identified as important in the aetiology of such tumours. We report a case where identification of an apparently sporadic metastatic phaeochromocytoma was found to be complicated by a synchronous paraganglioma of the vagus nerve in a patient with a pathogenic mutation of the SDHB gene.

Case: A 36-year-old man presented to the emergency department due to right iliac fossa pain and fever. Laparotomy and appendicectomy was carried out but no abnormality detected. An abdominal CT scan indicated the presence of a 5.4×5.2×6.8 cm retroperitoneal para-aortic mass. No lymphadenopathy was noted. 24 hour urinary excretion of noradrenaline 7589 nmol (<780) and adrenaline 282 nmol (<80) and serum chromogranin-A 50U/l (<21.8) were elevated. Excision revealed an extra-adrenal phaeochromocytoma with lymphovascular permeation and a lymph node containing metastatic tumour. Catecholamine excretion returned to normal. CT scanning identified a 2.5×2×3 cm neck mass with cervical lymphadenopathy. MIBG scanning was normal. PET scanning revealed an FDG avid lesion in the right mid-cervical region. Excision of a vagal nerve paragnglioma was carried out. The patient now has swallowing difficulties. None of the common mutations were found on analysis of the VHL gene and RET proto-oncogene. The R90X mutation was found in exon 3 of the SDHB gene. Family members with the SDHB mutation are being screened for further neuroendocrine tumours.

Discussion: Genetic screening in patients with extra-adrenal catecholamine secreting tumours is important. SDHB mutations appear to be associated with paragangliomas with malignant potential. Vagal nerve paragangliomas are rare and involve arduous surgical procedures and outcomes.